Large capacity rechargeable batteries are currently being investigated for use in electric vehicles. The ultimate feasibility of electric vehicles depends on significantly reducing the associated costs. Reduction in the costs of battery assemblies is particularly important.
Lithium ion batteries are an important type of battery technology. Most battery assemblies, including lithium ion battery assemblies, include a plurality of individual electrochemical cells. Typically, such electrochemical cells include an anode, a cathode, and a separator interposed between the anode and cathode. Typically, the anode includes a metal sheet or foil (usually copper metal) over-coated with a graphitic layer. Similarly, the cathode usually includes a metal sheet or foil (usually aluminum metal) over-coated with a lithium-containing layer. Finally, electrochemical cells include an electrolyte which is interposed between the anode and the cathode. Terminals allow the generated electricity to be used in an external circuit. Electrochemical cells produce electricity via an electrochemical reaction.
For high power and high energy applications, a plurality of battery cells are utilized and assembled into a battery module. Moreover, such battery modules include a plurality of metallic (e.g., copper and/or aluminum) cooling fins interspersed between battery cells in a parallel wired battery cell pair. Compression foam pads are typically interspersed between some battery cell pairs. With a high number of cooling fins, small temperature differences can be achieved. However, in order to reduce the cost of the battery, a low number of fins is desired.
Accordingly, there is a need for improved battery module assemblies and for methods of constructing such battery module assemblies.